Without checking this: Reference is an arbitrary string, isn’t it? Often seen like demo_1, demo_2, etc. It’s just a coincidence that this string happens to be a number in your case.

Product IDs are pretty much unchangeable. One can change them in the database, of course, but this would break relationships to pretty much all other tables. If you insist on a particular ID, delete the product and re-create it via CSV import. Regular product creation doesn’t even allow to set a particular ID.

As far as I know you can change the product ID only later in your mysql. When creating the products, the next highest number is automatically generated. If you have already had several products in it, but you have deleted them later, the next highest number of the last data set will still be used, even if this dataset (product) no longer exists.
In my opinion, you can only bypass this via CSV import.

@Traumflug and @zimmer-media I always use a CSV but this one time, of course, I decided to manually create a product. I’ll continue creating my new CSV with a new product and the number I hope to get and see what happens. That was what I was doing that prompted this question. If it stays at 500 plus for both fields, I’ll move along.

Product IDs are pretty much unchangeable. One can change them in the database, of course, but this would break relationships to pretty much all other tables. If you insist on a particular ID, delete the product and re-create it via CSV import. Regular product creation doesn’t even allow to set a particular ID.

I deleted the product and created it via CSV and all is back the way I want it. The product ID and Reference ID now match and increase from the correct next number.